MachineDominators.h revision 55ba691dce40d2af5a8f01ceacbe3734d90005b3 
1//=- llvm/CodeGen/MachineDominators.h - Machine Dom Calculation --*- C++ -*-==//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines classes mirroring those in llvm/Analysis/Dominators.h,
11// but for target-specific code rather than target-independent IR.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CODEGEN_MACHINEDOMINATORS_H
16#define LLVM_CODEGEN_MACHINEDOMINATORS_H
17
18#include "llvm/Analysis/DominatorInternals.h"
19#include "llvm/Analysis/Dominators.h"
20#include "llvm/CodeGen/MachineBasicBlock.h"
21#include "llvm/CodeGen/MachineFunction.h"
22#include "llvm/CodeGen/MachineFunctionPass.h"
23
24namespace llvm {
25
26template<>
27inline void DominatorTreeBase<MachineBasicBlock>::addRoot(MachineBasicBlock* MBB) {
28  this->Roots.push_back(MBB);
29}
30
31EXTERN_TEMPLATE_INSTANTIATION(class DomTreeNodeBase<MachineBasicBlock>);
32EXTERN_TEMPLATE_INSTANTIATION(class DominatorTreeBase<MachineBasicBlock>);
33
34typedef DomTreeNodeBase<MachineBasicBlock> MachineDomTreeNode;
35
36//===-------------------------------------
37/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
38/// compute a normal dominator tree.
39///
40class MachineDominatorTree : public MachineFunctionPass {
41public:
42  static char ID; // Pass ID, replacement for typeid
43  DominatorTreeBase<MachineBasicBlock>* DT;
44
45  MachineDominatorTree();
46
47  ~MachineDominatorTree();
48
49  DominatorTreeBase<MachineBasicBlock>& getBase() { return *DT; }
50
51  virtual void getAnalysisUsage(AnalysisUsage &AU) const;
52
53  /// getRoots -  Return the root blocks of the current CFG.  This may include
54  /// multiple blocks if we are computing post dominators.  For forward
55  /// dominators, this will always be a single block (the entry node).
56  ///
57  inline const std::vector<MachineBasicBlock*> &getRoots() const {
58    return DT->getRoots();
59  }
60
61  inline MachineBasicBlock *getRoot() const {
62    return DT->getRoot();
63  }
64
65  inline MachineDomTreeNode *getRootNode() const {
66    return DT->getRootNode();
67  }
68
69  virtual bool runOnMachineFunction(MachineFunction &F);
70
71  inline bool dominates(const MachineDomTreeNode* A,
72                        const MachineDomTreeNode* B) const {
73    return DT->dominates(A, B);
74  }
75
76  inline bool dominates(const MachineBasicBlock* A,
77                        const MachineBasicBlock* B) const {
78    return DT->dominates(A, B);
79  }
80
81  // dominates - Return true if A dominates B. This performs the
82  // special checks necessary if A and B are in the same basic block.
83  bool dominates(MachineInstr *A, MachineInstr *B) const {
84    MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
85    if (BBA != BBB) return DT->dominates(BBA, BBB);
86
87    // Loop through the basic block until we find A or B.
88    MachineBasicBlock::iterator I = BBA->begin();
89    for (; &*I != A && &*I != B; ++I)
90      /*empty*/ ;
91
92    //if(!DT.IsPostDominators) {
93      // A dominates B if it is found first in the basic block.
94      return &*I == A;
95    //} else {
96    //  // A post-dominates B if B is found first in the basic block.
97    //  return &*I == B;
98    //}
99  }
100
101  inline bool properlyDominates(const MachineDomTreeNode* A,
102                                const MachineDomTreeNode* B) const {
103    return DT->properlyDominates(A, B);
104  }
105
106  inline bool properlyDominates(const MachineBasicBlock* A,
107                                const MachineBasicBlock* B) const {
108    return DT->properlyDominates(A, B);
109  }
110
111  /// findNearestCommonDominator - Find nearest common dominator basic block
112  /// for basic block A and B. If there is no such block then return NULL.
113  inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
114                                                       MachineBasicBlock *B) {
115    return DT->findNearestCommonDominator(A, B);
116  }
117
118  inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
119    return DT->getNode(BB);
120  }
121
122  /// getNode - return the (Post)DominatorTree node for the specified basic
123  /// block.  This is the same as using operator[] on this class.
124  ///
125  inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
126    return DT->getNode(BB);
127  }
128
129  /// addNewBlock - Add a new node to the dominator tree information.  This
130  /// creates a new node as a child of DomBB dominator node,linking it into
131  /// the children list of the immediate dominator.
132  inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
133                                         MachineBasicBlock *DomBB) {
134    return DT->addNewBlock(BB, DomBB);
135  }
136
137  /// changeImmediateDominator - This method is used to update the dominator
138  /// tree information when a node's immediate dominator changes.
139  ///
140  inline void changeImmediateDominator(MachineBasicBlock *N,
141                                       MachineBasicBlock* NewIDom) {
142    DT->changeImmediateDominator(N, NewIDom);
143  }
144
145  inline void changeImmediateDominator(MachineDomTreeNode *N,
146                                       MachineDomTreeNode* NewIDom) {
147    DT->changeImmediateDominator(N, NewIDom);
148  }
149
150  /// eraseNode - Removes a node from  the dominator tree. Block must not
151  /// dominate any other blocks. Removes node from its immediate dominator's
152  /// children list. Deletes dominator node associated with basic block BB.
153  inline void eraseNode(MachineBasicBlock *BB) {
154    DT->eraseNode(BB);
155  }
156
157  /// splitBlock - BB is split and now it has one successor. Update dominator
158  /// tree to reflect this change.
159  inline void splitBlock(MachineBasicBlock* NewBB) {
160    DT->splitBlock(NewBB);
161  }
162
163  /// isReachableFromEntry - Return true if A is dominated by the entry
164  /// block of the function containing it.
165  bool isReachableFromEntry(const MachineBasicBlock *A) {
166    return DT->isReachableFromEntry(A);
167  }
168
169  virtual void releaseMemory();
170
171  virtual void print(raw_ostream &OS, const Module*) const;
172};
173
174//===-------------------------------------
175/// DominatorTree GraphTraits specialization so the DominatorTree can be
176/// iterable by generic graph iterators.
177///
178
179template<class T> struct GraphTraits;
180
181template <> struct GraphTraits<MachineDomTreeNode *> {
182  typedef MachineDomTreeNode NodeType;
183  typedef NodeType::iterator  ChildIteratorType;
184
185  static NodeType *getEntryNode(NodeType *N) {
186    return N;
187  }
188  static inline ChildIteratorType child_begin(NodeType* N) {
189    return N->begin();
190  }
191  static inline ChildIteratorType child_end(NodeType* N) {
192    return N->end();
193  }
194};
195
196template <> struct GraphTraits<MachineDominatorTree*>
197  : public GraphTraits<MachineDomTreeNode *> {
198  static NodeType *getEntryNode(MachineDominatorTree *DT) {
199    return DT->getRootNode();
200  }
201};
202
203}
204
205#endif
206